/* ====================================================================
 * The Apache Software License, Version 1.1
 *
 * Copyright (c) 2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache Lucene" must not be used to endorse or promote products
 *    derived from this software without prior written permission. For
 *    written permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    "Apache Lucene", nor may "Apache" appear in their name, without
 *    prior written permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

using System;

using DotnetPark.NLucene.Store;

namespace DotnetPark.NLucene.Index
{
	internal class SegmentTermPositions : SegmentTermDocs, ITermPositions 
	{
		private InputStream proxStream;
		private int proxCount;
		private int position;
  
		internal SegmentTermPositions(SegmentReader p) : base(p) 
		{
			this.proxStream = (InputStream)parent.ProxStream.Clone();
		}

		internal override void Seek(TermInfo ti) 
		{
			base.Seek(ti);
			if (ti != null)
				proxStream.Seek(ti.ProxPointer);
			else
				proxCount = 0;
		}

		public override void Close() 
		{
			base.Close();
			proxStream.Close();
		}

		public int NextPosition() 
		{
			proxCount--;
			return position += proxStream.ReadVInt();
		}

		protected override void SkippingDoc()
		{
			for (int f = Freq(); f > 0; f--)		  // skip all positions
				proxStream.ReadVInt();
		}

		public override bool Next()
		{
			for (int f = proxCount; f > 0; f--)		  // skip unread positions
				proxStream.ReadVInt();

			if (base.Next()) 
			{				  // run super
				proxCount = Freq();				  // note frequency
				position = 0;				  // reset position
				return true;
			}
			return false;
		}

		public override int Read(int[] docs, int[] freqs)
		{
			throw new Exception();
		}
	}
}
